"We are delivering the green games (and) dramatically enhancing the environmental situation," Chernyshenko said. "This is new to our country. This is the first step to demonstrate that you can build an environment in harmony with nature."

However many environmentalists bitterly reject such talk, bemoaning wrecked habitat, destroyed wildlife populations and bungled attempts to remedy the consequences of a massive program to ready Sochi for Friday's opening ceremony.

'A huge task'

Olympstroi, the state corporation overseeing the Olympic construction program, acknowledges that the work has affected a massive area of Sochi National Park -- 3,500 hectares (8,750 acres) in all -- but insists that every effort has been made to avoid damage to the environment.

Gleb Vatletsov, head of the company's environmental department, said some proposed venues were ruled out, and some rare species were moved away from certain ski sites.

In addition to setting up the Ornithological Park, Olympic contractors planted 1.5 million new trees -- three for every one that was cut down in the Sochi National Park to make way for Olympic sites.

"It was a huge task -- we are not ashamed to talk about it," Vatletsov told AFP.